Alzheimer DiseaseCLeAR-ADNCT07393113
CLarifying ABCB1's Role in Alzheimer's Disease
An observational study of Alzheimer Disease, run by Assistance Publique - Hôpitaux de Paris at 1 site in France.
Trial summary
Alzheimer's disease is biologically defined by the accumulation of amyloid beta and tau protein, identified using cerebrospinal fluid biomarkers. The ABCB1 gene, which encodes P-glycoprotein involved in amyloid beta efflux across the blood-brain barrier, may influence Alzheimer's disease risk. Read more about this study
- Who is it for?
- Ages 50 years and older
- Conditions the study is for
- Alzheimer Disease
- What is being tested?
- ABCB1 genotyping
- How many people
- 510 participants
- Where
- 1 siteFrance
- Study dates
- 25 Oct 2023to 31 Dec 2025
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 50 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Patients followed in a memory clinic who underwent a comprehensive clinical and paraclinical assessment, including cerebrospinal fluid biomarkers.
Who may be able to join
- age ≥ 50 years,
- available cerebrospinal fluid biomarker results,
- an available and usable DNA sample,
- and consent for future research use within the biobank.
Who cannot join
- the presence of an active non-degenerative neurological disorder (for example, multiple sclerosis, infections, or tumors),
- and missing data regarding APOE genotyping or cardiovascular risk factors
Trial locations and contacts
1 site in 1 country.
About this study
Official title: CLarifying ABCB1's Role in Amyloid Efflux and Alzheimer's Disease Risk
Alzheimer's disease is biologically defined by the accumulation of amyloid beta and tau protein, identified using cerebrospinal fluid biomarkers. The ABCB1 gene, which encodes P-glycoprotein involved in amyloid beta efflux across the blood-brain barrier, may influence Alzheimer's disease risk. We hypothesize that certain functional ABCB1 polymorphisms impair amyloid beta clearance, thereby promoting the development of biologically defined Alzheimer's disease.
Read the detailed description
A case-control study comparing the distribution of three functional ABCB1 gene polymorphisms (3435C>T, 2677G>T/A, 1236C>T) in patients with biologically defined Alzheimer's disease versus neurological controls. We will also analyze the distribution of haplotypes derived from the combination of these three polymorphisms and investigate potential interactions between these polymorphisms and the APOE genotype, particularly the presence of the ε4 allele.
- Conditions
- Alzheimer Disease
- Being tested
- ABCB1 genotyping
- Keywords
- Alzheimer Disease, P-glycoprotein
- Medical subject headings
- Alzheimer Disease
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ABCB1 genotypingGenetic
Genotyping of three single nucleotide polymorphisms (3435C>T, 2677G>T/A, and 1236C>T) associated with variation in P-glycoprotein activity, using DNA samples stored in a biobank.
| Study group | Role | What they receive |
|---|---|---|
| Patients with cerebrospinal fluid amyloid and phosphorylated tau biomarkers (A+T+) | Not described Receives: Genetic: ABCB1 genotyping | |
| Patients without cerebrospinal fluid amyloid, phosphorylated tau and total tau biomarkers (A-T-N-) | Not described Receives: Genetic: ABCB1 genotyping |
What is being measured
The primary outcome is the main question the study is designed to answer.
Allele and genotype frequencies of ABCB1 single nucleotide polymorphisms (3435C>T, 2677G>T/A, and 1236C>T)
Allele and genotype frequencies of the ABCB1 single nucleotide polymorphisms 3435C>T, 2677G>T/A, and 1236C>T, determined by genotyping from genomic DNA, will be compared between:
- patients with biologically defined Alzheimer's disease (A+T+Nx), and
- neurological control participants with a negative biomarker profile (A-T-N-). Data will be summarized as allele frequencies and genotype distributions in each group.
Measured: Baseline (at the time of biological sampling and clinical assessment)
Secondary outcomes (2)
Haplotype frequencies of ABCB1 polymorphisms (3435C>T, 2677G>T/A, and 1236C>T)
Haplotype frequencies derived from the combination of the ABCB1 single nucleotide polymorphisms 3435C>T, 2677G>T/A, and 1236C>T, inferred from genotyping data, will be compared between:
- patients with biologically defined Alzheimer's disease (A+T+Nx), and
- neurological control participants with a negative biomarker profile (A-T-N-). Haplotypes will be summarized as frequency distributions within each group.
Measured: Baseline (at the time of biological sampling and clinical assessment)
Distribution of ABCB1 polymorphisms stratified by APOE ε4 carrier status
The distribution of ABCB1 single nucleotide polymorphisms (3435C>T, 2677G>T/A, and 1236C>T) will be assessed according to APOE ε4 carrier status (ε4 carriers vs non-carriers) in:
- patients with biologically defined Alzheimer's disease (A+T+Nx), and
- neurological control participants with a negative biomarker profile (A-T-N-). ABCB1 allele and genotype frequencies will be summarized within each APOE ε4 stratum.
Measured: Baseline (at the time of biological sampling and clinical assessment)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 Feb 2026
- Study start25 Oct 2023
- Primary completion31 Dec 2025
- Study completion31 Dec 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Alzheimer DiseaseStudies of the same condition, open and under way.
- More trials run by Assistance Publique - Hôpitaux de ParisThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case-control
- Time perspective
- Retrospective
- Enrolment
- 510 participants (actual)
Sponsor and investigators
- Lead sponsor
- Assistance Publique - Hôpitaux de Paris
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07393113
- Sponsor's protocol ID
- APHP251732
- Acronym
- CLeAR-AD
- Status last verified
- Jan 2026
- First submitted
- 19 Jan 2026
- Last updated
- 6 Feb 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 6 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- CLarifying ABCB1's Role in Amyloid Efflux and Alzheimer's Disease Risk
- ClinicalTrials.gov ID
- NCT07393113
- Acronym / sponsor ID
- CLeAR-AD / APHP251732
- Conditions
- Alzheimer Disease
- Keywords
- Alzheimer Disease, P-glycoprotein
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 510 participants (actual)
- Lead sponsor
- Assistance Publique - Hôpitaux de ParisUniversity, hospital or other
- Study start
- 25 Oct 2023 (actual)
- Primary completion
- 31 Dec 2025 (actual)
- Study completion
- 31 Dec 2025 (actual)
- First posted
- 6 Feb 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Alzheimer's disease is biologically defined by the accumulation of amyloid beta and tau protein, identified using cerebrospinal fluid biomarkers. The ABCB1 gene, which encodes P-glycoprotein involved in amyloid beta efflux across the blood-brain barrier, may influence Alzheimer's disease risk. We hypothesize that certain functional ABCB1 polymorphisms impair amyloid beta clearance, thereby promoting the development of biologically defined Alzheimer's disease.
Detailed description
A case-control study comparing the distribution of three functional ABCB1 gene polymorphisms (3435C>T, 2677G>T/A, 1236C>T) in patients with biologically defined Alzheimer's disease versus neurological controls. We will also analyze the distribution of haplotypes derived from the combination of these three polymorphisms and investigate potential interactions between these polymorphisms and the APOE genotype, particularly the presence of the ε4 allele.
Study design
- Observational model
- Case-control
- Time perspective
- Retrospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Patients with cerebrospinal fluid amyloid and phosphorylated tau biomarkers (A+T+) | – | Genetic: ABCB1 genotyping |
| Patients without cerebrospinal fluid amyloid, phosphorylated tau and total tau biomarkers (A-T-N-) | – | Genetic: ABCB1 genotyping |
Who may qualify
- Ages
- 50 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Patients followed in a memory clinic who underwent a comprehensive clinical and paraclinical assessment, including cerebrospinal fluid biomarkers.
Key inclusion criteria (4 listed)
- age ≥ 50 years,
- available cerebrospinal fluid biomarker results,
- an available and usable DNA sample,
- and consent for future research use within the biobank.
Key exclusion criteria (2 listed)
- the presence of an active non-degenerative neurological disorder (for example, multiple sclerosis, infections, or tumors),
- and missing data regarding APOE genotyping or cardiovascular risk factors
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| ABCB1 genotypingGenotyping of three single nucleotide polymorphisms (3435C>T, 2677G>T/A, and 1236C>T) associated with variation in P-glycoprotein activity, using DNA samples stored in a biobank. | Genetic | Patients with cerebrospinal fluid amyloid and phosphorylated tau biomarkers (A+T+), Patients without cerebrospinal fluid amyloid, phosphorylated tau and total tau biomarkers (A-T-N-) |
Primary outcome
Allele and genotype frequencies of ABCB1 single nucleotide polymorphisms (3435C>T, 2677G>T/A, and 1236C>T)
Time frame: Baseline (at the time of biological sampling and clinical assessment)
Allele and genotype frequencies of the ABCB1 single nucleotide polymorphisms 3435C>T, 2677G>T/A, and 1236C>T, determined by genotyping from genomic DNA, will be compared between: * patients with biologically defined Alzheimer's disease (A+T+Nx), and * neurological control participants with a negative biomarker profile (A-T-N-). Data will be summarized as allele frequencies and genotype distributions in each group.
2 secondary outcomes
Haplotype frequencies of ABCB1 polymorphisms (3435C>T, 2677G>T/A, and 1236C>T)
Time frame: Baseline (at the time of biological sampling and clinical assessment)
Distribution of ABCB1 polymorphisms stratified by APOE ε4 carrier status
Time frame: Baseline (at the time of biological sampling and clinical assessment)
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Feb 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Alzheimer Disease, run by Assistance Publique - Hôpitaux de Paris at 1 site in France.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 6 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in France. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Allele and genotype frequencies of ABCB1 single nucleotide polymorphisms (3435C>T, 2677G>T/A, and 1236C>T) (time frame: Baseline (at the time of biological sampling and clinical assessment)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 Feb 2026.